Sanitization of databases for refined privacy trade-offs

In this paper, we propose a new heuristic algorithm called the QIBC algorithm that improves the privacy of sensitive knowledge (as itemsets) by blocking more inference channels. We show that the existing sanitizing algorithms for such task have fundamental drawbacks. We show that previous methods remove more knowledge than necessary for unjustified reasons or heuristically attempt to remove the minimum frequent non-sensitive knowledge but leave open inference channels that lead to discovery of hidden sensitive knowledge. We formalize the refined problem and prove it is NP-hard. Finally, experimental results show the practicality of the new QIBC algorithm.